There have been known network services that enable data such as audio, video, and messages to be exchanged between users via a network. In such network services, for example, account data of each user is stored in an information processing device such as a server, and pieces of the account data corresponding to users, who are allowed to exchange data with each other, are associated with each other. For the users who are allowed to exchange data with each other, when one of the users transmits data such as a message to the information processing device by specifying the other user, the information processing device receives the data and transmits the received data to the other user.
There have also been known portable game machines. Patent Literature 1 discloses a technology that enables a game to be executed based on a program downloaded from a master, in a state in which power supply from the master is cut off. There have also been known technologies for exchanging data between information processing terminals such as the portable game machines, mobile phones, and small personal computers by peer-to-peer (P2P) communication using infrared ray, wireless LAN, or the like, for example, without being mediated by an information processing device such as a server.